It's really up to you how they're build but since I don't have the proper equipment for TDH FD, I run TDW (Running TDW also can save you an extra turn with the lightning imbue). Whenever I run double 2B, I usually go Supreme Support Weapon --> true charge volt --> true charge blade --> then LB Wreck everything lmao. Your choices are numerous. And also if you really want to get the most out of her, I would max her. However, I see you have other choices for DPS so it's up to you on whether you think it's worth or not. Personally I think it is but I have a lot of 2B friends so I am just saving my 2 spare 2Bs until I stop being indecisive about how I want to use them.

You can't have both with FD if you want 2B to be your breaker, you need at last one with VC, otherwise you won't be able to keep the break up all time.

But I wouldn't use TDH 2B if she is there for the breaks. TDW 2B is more consistent on generatig the LB crystas (because she cast True Charge Blade twice and don't need to lose turns with imbue). The damage still high enough while you have 100% break uptime.

You can't have both with FD if you want 2B to be your breaker, you need at last one with VC, otherwise you won't be able to keep the break up all time.

But I wouldn't use TDH 2B if she is there for the breaks. TDW 2B is more consistent on generatig the LB crystas (because she cast True Charge Blade twice and don't need to lose turns with imbue). The damage still high enough while you have 100% break uptime.

Just build one and one. All that matters is the lb. The limit burst will chain fine with tdh and tdw builds. you will get much more damage using a fd tdh build but still get the breaks having a vc build. you will still hit some chains but the way to go is use a lightning sword on the one with VC. Then you can imperil lightning with that while imbuing lightning with the fd 2b. this will be done on turn 2. turn 3 is the lb generator which will chain for half and should be enough to have a limit burst.

The only time you aren't chaining is when you have to imbue and imperil. But thats ok because the imperil move is not a chaining move anyway, and using a lightning weapon will save you that turn of imbuing.